1. Field of the Invention
The invention relates to a press for producing shaped parts from powder material, the press comprising a top punch holder arranged on a transverse part that is supported by lifting rods, in particular, a press further comprising an eccentric crank drive moving the top punch by means of the lifting rods and the transverse part.
2. Description of the Related Art
The stroke/time course of such presses follows in the case of the conventional uniform rotary drive essentially a sine curve that is slightly modified as a result of the slanted positioning of the connecting rods of the eccentric crank drive. However, deviations from this crank drive function are generated by the elastic expansion of the lifting rods and the connecting rods as well as elastic deformations of other parts. Movements within bearing plays etc. can be eliminated by providing pretension.
When planning the applications and the construction of the pressing tools, the operators of the presses use the crank drive function as a base and, if needed, take into account the error in such a way that the top punch position is lowered by the expansion length that has been measured beforehand.